System for eliminating or greatly reducing the errors in gyroscopic devices or the like



Sept. 4, 1951 R BEACOM 2,566,305

SYSTEM FOR ELIMINATING OR GREATLY REDUCING :I'HE ERRORS IN GYROSCOPIC DEVICES OR THE LIKE filed Jan. 8, 1947 2 Sheets-Sheet l I N VEN TOR. #42012 at 55409 I 77 IQ/YEK M 17/fEA 7- P 1951 H. R. BEACOM 2,566,305

SYSTEM FOR ELIMINATING OR GREATLY REDUCING THE ERRORS IN GYROSCOPIC DEVICES OR THE LIKE Filed Jan. 8, 1947 2 Sheets-Sheet 2 INVENTOR. #92049 6 13154 0/14 ing or greatly reducing the through proper pick-off means.

scopes slightly pendulous so Patented Sept. 4, 1951 SYSTEM FOR ELIMINATING OR GREATLY REDUCING THE ERRORS IN GYROSCOPIC DEVICES OR THE LIKE Harold R. Beacom, Osborn, Ohio Application January 8, 1947, Serial No. 720,893

ct of March a, 1883, as 1928; 310 0. G. 757) 9 Claims.

(Granted under the a amended April 30,

The invention described hereinmay oe manufactured and used by or for the Government for governmental purposes without payment to me of any royalty thereon.

This invention relates to a device for eliminaterrors or apparent errors in gyroscopes, or the like, by reducing a multiple of signals from a multiplicity of associated gyroscope actuated signal transmitting means to an average single signal.

The present invention emanated from a satisfactory solution to the problem of eliminating or substantially reducing the errors or apparent errors in gyroscopic devices. It is well understood that artificial and natural forces act on gyroscopes which introduce errors and apparent errors affecting their designed purpose, but by the use of two similarl independently mounted like gyroscopes operative to rotate in opposite direc tions the errors are substantially neutralized The use of two similarlyindependently mounted like gyroscopes is explained in that centrifugal, acceleration, de-

celeration, or friction forces applied to the gyroscopes will be in the same direction for both gyroscope assemblies but since the directions of rotation of the gyroscopes are opposite the resuiting precessions of the gyroscope axes of spin will be equal but in opposite directions. The mountings for the gyroscopes allows 360 degrees of free movement in any rotative direction. The apparent errors caused by the rotation of the earth or movement of the gyroscope around the earth are greatly reduced by making the gyrothat any movement around theearths surface or the rotation of the earth will cause a pendulous torque to be applied to the gyroscopes in the same direction. Since the spin of the gyroscopes is in opposite direc tions the gyroscopic precessions will be equal but in approxmately opposte drectons and wll almost completely cancel out at a pont of reference.

Since the gyroscopes arranged in this manner operate to produce the errors in substantially equal and opposite directions along the spin axis a self-synchronous transmitter pick-01f means is very effective to average the signals, originating at the gyroscopes, to be transmitted to a signal responsive receiver operative to control an operated element. The stators of the self -synchronous transmitters on the two gyroscopes and of the self-synchronous receiver are electrically connected in parallel whereby the signals induced in the stators of the transmitters are resolved into a single average signal by the receiver. In order to avoid any errors to be introduced in the gyroscopes, as a result of the feed-back in the stator circuits of the self synchronous transmitters causing a torque on the rotors, the rotor currents are kept very lowin the transmitters and the averaged signal received by the receiver is amplified to perform its function. The selfsynchronous transmitter-receiver system allows accurate operation throughout a full 360 degrees of movement and any mechanical friction thereof, although slight, will be canceled by the opposite precessions of the gyroscopes. Other known devices, as resistance or rheostat electric signal transmitter and receiver means, are not adaptable for efficient operation throughout360 degrees of rotative movement and have considerable detrimental frictional resistance. The present invention provides a device having a high degree of accuracy necessary to precision instruments. The device is simple in construction and reliable in operation making its use attractive for precision work.

It is a primary object of this invention to provide a gyroscopically operated device in which at least two independently mountedoppositely rotatable gyroscopes each have a signal transmitting means to actuate an operated elementor elements, the signal transmitting means being interrelated to average the angular difference between the gyroscopes.

It is another object of this invention to provide a method of eliminating or greatly reducing errors or apparent errors in gyroscopic devices, or the like, by averaging a multiple of signals ob tained from a multiple of signal pick-off means of a multiple of gyroscopes for transmission to receiver elements responsive to an average signal.

It is a further object of this invention to provide a device forreducing a multiple of electric signals produced by a multiple of signal transmitting means to an average single signal.

It is still a further object of this invention, to provide a gyroscopic attitude indicating device utilizing two independently universally mounted oppositely rotatable gyroscopes having the same spin axis orientation and corresponding axes of motion, a self-synchronous transmitter in, 0perative relation with each of the axes of motion of each of the gyroscopes for producing asignal, the self-synchronoustransmitters of corresponding axes of motion being connected in parallel for averaging the amplitude of the signal that is transmitted to the corresponding self-synchronous receiver on an indicator repeater where the signal is operative through the self-synchronous tion in accordance with the average position of the two gyroscopes relative to their mounts.

Other objects, advantages, and uses will become apparentupon consideration of the follow- I a ing detailed description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a diagrammatic illustration of themvention showing the external electrical circuit arrangement associated therewith;

Fig. 2 is a diagram of thekelectrical circuit illustrated in this invention with the mechanical drive connection shown schematically as related to the electric receiver and low inertia motor; and

Fig. 3 is a graph of the amplitudes of the E. M. F. generated in one leg of a stator winding of cooperating self-synchronousitransmitters and the average amplitude of the F. inthis leg ings, or the like.

;:movement with respect to their supporting frame :byinner and outer gimbal ringsv I I, I2 and ,I 5, :14, respectively. The gym rotors fi and ll are rotatable about -a spin axison bearingspreferabl-yof the frictionless type,-in the inner gimbal airin s; II and; I3,.-respectively,:asshown at I5 and ;,I6,-;inthe .weltknown manner. 'The inner gimbal rings II and I3 are-each rotatabl on adia- ,;metr-ieal axis, which-is perpendicular to the re- ,;spective gyro rotorespin axis, by shaft extension mean II, I8 and I9, 20, respectively, in bearings, preferably of.-the,frictionless type,=in the outer gi-mbal rings I2 andJ 4,. respectively. The outer gimbal rings; I2 and=t4 are rotatably mounted in gthe frames-1 ,and.-8 on diametrical axes by shaft extensions 2 I 22 and -23, 24,; respectively. From the above-description it may, be understood that the yroscopes have freedom of movement throughout 360 degrees inany rotative-direction.

-The-shaft-ex-tensionsJfl and I9 ofthe two -,-gyroscope assemblies are operativelyconnected tc; the rotors ofself-synchronous transmittersZB land-.21 the .statorspf ,whicharesecured to the gimbal rings I2 and I4, respectively. .The gimbal rings I2 ..,and I4 --may .bev enlarged or otherwise -,weighted diametrically opposite. to. the self -synchronous transmittersinozgderlto obtain perfect {balance of thesegimbaI rings on their shaft extensions 2l, 22 and, 23,2 1, respectively. Electric cables 28 .and 2.9 connect the self-synchronous ,transmitters 26 an d 21, respectively, with slip rings 3I,,32 and 33, 3 4 on the shaft extensions 22 and24 of the gyroscopes, respectively, the slip rings 3| and'33 connect rotor ,windings, shown in diagram as 35 and-31 in Fig. .2, and the slip rings -32, 34 connect stator windings in the self-synchronous transmitter 26 and 21,,shownas 38 and 39 in Fig.2. w

-The shaft extensions2I and 23 are mechanically connected to rotors of self-synchronous 'tra'nsmitters 4| and 42, respectively. stators of the self-synchronou -transmitters 4| and 42 are {fastened to the framesT-and 8 of the tw gyroscope assemblies, respectively. Electrical conductors 43, 44 and 45, 46-enter theself-Synchro- =nous -transmitters M and 42 respectively, the --c onductors 43 and 45 being'connected to rotor ;windings-and theconductors-44 and 36 being connected to statorwindings.

"I he gyroscope assembliesare made slightly pendulouslnot shown) in the well known manner for the purpose later'to'be described. The gyroscope assemblies could be on separate frames and at remote points,-- or the-gyroscope assemblies "4 may be assembled on the sanie frame; if the shaft extensions 2I,22 and 23, 24 are arranged in ,parallel relation.

Mounted at some desirable place in an air- .5 -craft,or othervehicle in which this device is used,

:is -a-repeater indicator assembly generally re- "ferred to by the reference character 5|. The in- ,dicator comprises a bifurcated member 52 rotatably supported by a shaft 53 on a frictionless .10 .type ofsbearing=54 set in the framework 55 of the aircraft instrument case, or the like. An attitud spherical segment 56 is rotatably mountedbysa, shaft;51;si,n the arms 58 and 59 of the :bifurcatedsmember 52 by frictionless type bear- .-A self-synchronous receiver v.ISI has a .,rotor meohanically--connected., totheshaft 51 of .the -attitudespherical segment. .56. A stator ..Of.,;t he

self-synchronous receiverjlxisrsecured to the =-arm-58 of: th bifurcated member .52. 1 An elec- .tric cable .62 is .arranged .to .pass through the b1- ;furcated member ,52., and shaft 53 to connect, a

rotor winding .of ..-.the SGIfrSYIlChI'OIIQHS receiver -;6I toslip ringsfiaand toconnectstator windings 1 to slip rings 64. The rotorwinding of the self- 7 synchronous: receiver. 6 I as illustrated in Fig. 2,

.is shown-as 65 ,.wh;ile.,.tl 1,e.-/ statonwindings are .shownas 66.

A low in rtia m0t0r,7|,1. h,as..a.,statOr. body fas- 130 tened to thearm 9 ..0f the-b furcated. member 52. and, a rotor mechafiicallyoonnwted to the -shaft. 51 of the .sphericalsegmentjfi. An electrical I cable 'lI ,passes ,tl ,1rough ,the bifurcated member 52,and.53 .connectineaj fixed phase stator v winding and a -variable,,pl,1as e stator ,winding,

illustrated ,as 13 ,and 114,, respect v ly, in.Eig.;2, of the,,low ;inertia..motorfll .1;o s1ip ringsg'w and spectively. Th rotor of the low iner motor I I designated.,,as .17., in .Fig.;2,...inclujdes a c ioneearemeans 18in its mechanicalcon- ,nection with ,the s haft 5Lfor providing smooth eificientactuation of the spherical segment 56. The bifurcated member L52 with its assembled parts is balancedabQllt its rotatable ,axis along .the shaft.53. l- .s f synchronous receiver 8|, similar to the self-synchronous receiver ,BI, has astator body member secured to aframework 82 that .is relatively immovable with respect tothe framework .55. A rotorin.the.-.selfsynchronous.re-

ceiver. 8| is. mechanically. connected to the shaft .53 and includes .a. rotor windingselectrically connectiblethrough conductors .23. ,Stator wind- ,ings in theself-synchronous receivers, 8 I are connected. byleads,8,4 to electrical conductors 85 in ,circuit with stator windings 44 and- 45 of the self-synchronous transmitters 4| and v:42, the sstator windingsall bcingconnected in parallel.

the low inertia; motors! I,-has-:a-:statcr body. memphase windinguandiav-variable-phase:winding electrically connecterbto theleads'i92.-and 93, respectively.

Twin amplifiers, illustrated at 95, are adapted to be connected to. a source of-alternating current through the-leads=96 '91, and-the =r0t0rs of the self-synchronous transmitters -=are adaptedto I be connected to the-same source of I alternatingcur- =rent supplythrough the conductors 98 and 99. -The 'fixed -phasewvinding -13 ;of the 'low inertia '75 -motor "'I I is connected through the conductors'IIlII particularly adaptable for a synchronous receiver is connected through the slip rings 03, brushes I06, and conductors I01 to the pitch amplifier I05. The stator windings 65 of the self -synchronous receiver GI are connected through slip rings 64, brushes I08, conductors I05, III), brushes III, H2, and slip rings 32 and 34 to the stator windings 38 and 39 of th self-synchronous transmitters, the stator windings all being connected in electrical parallel relation. Conductors H5 and HE connect the rotor winding of the self-synchronous receiver BI and the variable phase winding of the low inertia motor 9|, respectively, to the other amplifier, generally referred to as the roll amplifier. The fixed phase of the low inertia, motor QI is connected with the alternating current supply lines through the leads 92. in the fixed phase circuit of each low inertia motor to obtain a proper phase relation between the fixed and variable phase windings for proper operation of the low inertia motors.

As illustrated, the above described invention is gyroscopic pitch and roll attitude indicator device with the gyroscope assemblies adapted to be taken through space in the direction indicated by the arrow therebetween. The self-synchronous transmitters 26, 21, self-synchronous receiver BI, low inertia motor 1!, and pitch amplifier I05 are all in one complete circuit arrangement to give a pitch registration on the spherical segment as seen through the window I20 on the instrument panel of the aircraft, or the like. The self-synchronous transmitters M, 52, self-synchronous receiver 8|, low inertia motor BI, and roll amplifier are all in another circuit to indicator 56.

As illustrated in Fig. 2 only one circuit arrangement for the indicating means is shown in the diagram since the self-synchronous electrical systems for both axes of motion are the same. The amplifier I05 has the primary winding of a transformer I2! connected with the alternating current supply through the leads 91. Current is taken from the secondary winding of the transformer I2I and passed through a full wave recti fying circuit including rectifying tube I22 and connected to the primary winding of a transformer I23 which is in series with a plate of an amplifier tube HA. The control grid of the amplifier tube I24 is coupled to the plate of an amplifier tube I25 by means of a condenser E25 and a resistor I21. Positive potential is supplied to the anode of the tube I25 through resistor l28 which is connected to the positive side of the power supply. The receiver rotor winding 65 is coupled to the grid of the amplifier tube I25 by transformer I29. The resulting amplified output of the amplifier tube i2 3 is applied to the variable phase winding 14 through the transformer lit. The fixed phase winding #3 of the low inertia motor H is connected in series with the condenser II1 across the alternating current supply 95. The valve of condenser H1 is such as to cause the current in the fixed phase winding 13 to be approximately 90 degrees out of phase with the current in the variable phase winding 14,

If the rotor winding 65 is in neutral position no voltage is induced therein and therefore there is scope axis to spiral,

, shift the gyro rotor spin axis slightly pendulous gyroscopes the low inertia motor 56 will assume its position,

no current in the variable phase" winding 14:

while if the rotor winding 65 is on one side of the neutral position the current in the variable phase winding 14 will lead the current in the fixed phase winding 13 by substantially degrees causing II to rotate in one direction; and if the rotor winding 65 is on the other side of the neutralposition the current in the variable phase winding 14 will lag the current in the fixed phase winding 13 by substantially 90 degrees causing rotation of thelow inertia motor H in thecpposite direction.

In operation, the gyroscopes are made to rotate, in the well known manner, in opposite directions and are erected for the initial point of reference. An erection system is not shown inasmuch as the erection system may be of any type provided the system used on both gyroscope assemblies 5 and 6, has the same erection rate, the same general characteristics, erects the gyroscope from small displacements without causing the gyroand is capable of being made totally inoperative during turns and/or periods of acceleration and deceleration or made inoperative for the axis affected. The spherical segment as seen through the window I20, in; proper relation to the earth by operation of the low inertia motors H and 9 through the self-synchronous and amplifier circuits. For the purpose of explanation let it be assumed that the device is being used in an aircraft which is flying such that the frames 1 and 8 are perfectly level and the self-synchronous each electrical sys- The indicasegment 56 as comthe window opening tem are at rest as shown in tor, comprising the spherical pared relative to indicia on pitch and zero roll. The spherical segment 56 of the indicator assembly 5i being stabilized by the gyroscopic system disclosed, the segment functions to establish a datum or positional reference means relative to the pitch and roll axes of the gyroscopic system and relative to the aircraft itself. Any maneuvering of the aircraft will cause registration by the indicator with respect to the pitch and roll of the aircraft. However, the maneuvering of the aircraft induces errors in the gyroscopes by reason of mechanical friction in the bearing parts and slip ring and brush parts, and by reason of the slightly pendulous arrangement of the gyroscopes producing a slight pendulous torque on the gyro rotors. The mechanical friction can not be completely overcome but similar construction of the two gyroscopes provides devices having equal mechanical resistance and consequently the pendulous torque will be similarly efiective on both gyroscopes. Since the gyro rotors are rotating in opposite directions any forces by reason of mechanical friction or pendulous torques tending to shift the gyro rotor axis results in precessions of the gyro rotors to in a direction 90 degreesfrom the effective resultant applied forces to effect deviations in equal but opposite directions. This angular deviation rotates the rotors of the self-synchronous transmitters 26, 21 and M, 42 in equal and opposite directions, respectively, which transmit electrical signals to the self-synchronous receivers BI and BI, respectively. By way of example, when the aircraft makes a turn the roll of the aircraft will be registered on the indicator but a centrifugal force will. be exerted on the producing a peniasee sos dulous torque extending-to. rotate them about their "taxes 2|, -22- ,and 23,. 24 respectively, and due to rtheegyroscopic action 'ofathe oppositely rotatable ,cific embodiment of -vwinding M to cause r e M the 1 inertia :motor I! inna directiomoe thegang lar position of the rotorxvinm Bifrom th neutral position, to rotate the shal m through the reductiongearing wand to rotat t r, and.

consequently the rotor winding-65, ta es neutral By rearranging the gyroscope assemblies a directional several cameras, etc. Although I have shown and described a spe- Iclaim: o

l. A gyroscopic device comprising, two similar independently and universally mounted gyroscopes including rotors driven in opposite directions of rotation on the respective spin axes thereof and each gyroscope having two axes of rotation perpendicular to each other with corresponding axes of said gyroscopes in approximate parallelism, self-synchronous transmitters operatively connected to said gyroscopes on each of said two axes of rotation and having stator windings on corresponding axes of rotation electrically connected in parallel relation with each other and with stator windings of separate selfsynchronous receivers, rotor windings in said transmitters for connection to an alternating cur rent source, an indicating instrumentincluding means mounted for rotation on two axes perpendicular to each other to establish a datum relative to the two axes of rotation of said gyroscopes,

shaft means on said-two axes of said instrument included means each connected to one of said selfsynchronous receivers and to an actuating motor, electrical coupling means between said self-synchronous receivers and said actuating motors, whereby the parallel connection of said stator windings on corresponding axes of rotation of said gyroscopes are operative to produce an average E. M., F. in the self-synchronous receivers for effecting operation of the corresponding actuating motors to produce instrument indication in accordance with the average angular deviation ofl the two gyroscopes about correspondingaxes of rotation.

2. A gyroscopic device for eliminating or greatly reducing the errors, induced therein comprising, two similar independently and universally mounted gyroscopes each' having an outer gimbal ring, an innergimbal ring and a central rotor mounted on bearings withinlthe .innergimbal ring, means mounting the two outer gimbal rings for rotation about parallel axes,;means mounting the two inner gimbal rings for, rotation within the outer gimbal rings on parallel axes perpendicular to said parallel axes of rotation of said outer gimbal rings, means mounting a rotor within each inner gimbal .ring forrotation about axes perpendicular tothe, axes ofrotation of said inner gimbal rings, ,means to cause rotation. of said two rotors in opposite directions at high speed, self-synchronous transmitters operatively connected to the r'es'pectiv gimbal rings at their axes of rotation, stator windings in said transmitters on corresponding axes of rotation connected in parallel relation with each other and with stator windings of self-synchronous receivers, rotor windings insaidtransmittersconnected to an alternating current source, ane means actuated jointly by said receivers for establishing a datum relative to the axes of rotation 'of said inner and outer gimbal rings in accordance with the average angular deviation of the two gyroscopes about corresponding axes of rotation of said gimbal rings. V n

3. A gyroscopic device for eliminating or greatly reducing the errors induced therein comprising, two similar independently and universally mounted gyroscopes each having an outer gimbal ring, an inner gimbal ring and a central rotor mounted on bearings w'ithinthe inner gimbal ring, meansmounting the-two outer gimbal rings for rotation aboutparallel axes, means mounting the two inner "gimbal rings io r rotation within theoutergimbal rings von parallel axes perpendicular to said parallel axes of rotation of said outer gimbal rings, means mounting a rotor within each inner gimbal ring for rotation about axes perpendicular to the axes of IO-- tation of said inner gimbal rings, means to cause rotation of said two rotors in opposite directions at high speed,self-synchronous transmitters operatively connected to the respective gimbal rings at their axes. of rotation-stator windings in said transmitters on corresponding axes oi rotation,

connected in parallel relation with each other and with stator windings of self-synchronous receivers, rotor windings in said transmitters connected to an, alternating current source, an indicating instrument including means. mounted forrotationon two axes perpendicular to each other to establish a datum relative to the two axes rotation otsaid gyroscopes, shaft means on said two axes of saidfinstrument included means each connected to one of said self-synchronous receivers andto an actuating motor, electrical cou ling meafns between said selfsynchronous receivers ands-aid actuating motors,

whereby the parallel connection of said stator; windings on corresponding axes of rotation of said E. in the self s'yr'ichronous receivers for efgyroscopesare operative to produce an average fec'ting" operation of the corresponding actuating motors to produceins'trument indication in ac nuisance the twofgyro's'copfes about corresponding axes of gl'mhal ring rotation M l, A gyroscopi independently and" scopes each having an outerlg'imbal ring, an in:- ner girnbal bearings wi g'imbalfifing, means mounting the twoputer gimbafrings for rotation "universan 'Inounted g ro;

thin "the inner about parallel axes, means mounting the two inner gimbal r'ings for rotationw'ithin the outer" gimbalrings oa'joarauei axes perpjendiculari to s'aid parallel axes or rotationoi said clute'rgirnba'l rings,'rneans moj1ntii1g a rotor within each gi'mbal rin for rotation about axes ularftothe xe or rotation of s'aid'ihner'gimbal rings, means tocauserotation of said two rotors in opposite directions'atl'high speed, similar sig' nal producing means'operatively connectedto the inner and outer m arnngs ofeach gyroscope on their respecti axes'of rotation, interconnecting means between "the 7 similar signal producing means on corresponding axes to provide separate portional to" the "averagesnguiar displacements of the inner and outer gimbal rings about their axes of rotatioiifafid'm'ea'ris actuateq jointlyb'y said sig al out uts rorestabnsning datum rentive to the axes of'r'otati'on of said inner and outer gimbalring's accor ance with the average angularcieviation orftne'twogy roscopes about cor'-' responding axes of rotation of said gimbal rings.

5; A gyrosccpic "devicecomprising; two similar independently and universally mounted gyro scopes mending rotors driven in opposite direc tions of rotation on the respective spin axes thereof and each gyroscope having two axes of rota tion perpendicularto each other "with corresponding axes of "said gyroscop'es in' approximate par allelisrn," self-synchronous" transmitters opera;- tively connected to'said gyroscope's'ori each of said two axes or rotatidriand including.field'windings,' interco'necting" means between the field windings of transmitters 'on'corresponding axes of rotation or said gyroscopes to provide separate" average signal outputs proportional to the average van gular displacements of the gyroscopes about corof said gyroscopes' witnthe averag'eangular deviation of l 0 "device comprising, two similar ring and a central rotor mounted perpendic average signal outputs proresponding. axes of' rotation, two separate self synchronous receivers including field windings? respectively energized bysaid separate average signalv outputs, an instrument including means tor, electrical coupling means between said selfsynchronous receivers and saidactuating motors, whereby said separate average signal outputs are operative to produce .an average E. M. F. in each self-synchronous receiver for effecting operation of-the corresponding actuating motors to produce instrument action through saidshaft means on.

said two axes in accordance. with the average angular deviation of the two gyroscopes about corresponding axes of rotation.

6.- A gyroscopic devic comprising, two similar.

independently mounted gyroscope assemblies including separate rotors driven in opposite directions of rotation on the respective spin axes thereof and each gyroscope assembly having means providing two axes ofrotation with corresponding axesof said gyroscope assemblies in approximate parallelism, self-synchronous transmitters operatively connected to said gyroscope assemblies on each of said two axes of rotation of each gyroscope-assembly, stator windings of the transmitter on one axisof one gyroscopeassembly being electrically connected in parallel relation with the stator. windings of the transmitter. on the corresponding axis ofthe'other gyroscop assembly and;with the stator windin ofa first self-synchronous receiver, stator windings of the other two. transmitters on corresponding axes of said.

gyroscope assemblies being; electrically connected inparallel relation with each ceiyer,..rotor. windingsineach of said transmit.- ters for connection to an source, andmeans actuated jointly by said firstand second self-synchronous receivers for. establishing adatum with. the, averageangular; deviation of V the; two

gyroscope assemblies; about corresponding axes of;

rotation 7. A, gyrosco ic ilar independently device comprising, two, sim; mounted gyroscope assemblies including. separate ,rotors 'drivenin opposite di-- rections of rotation onthe respectivespinaxes roscope assembly having thereof and each. means providing two axes 1 of rotation. with corresponding axes ofsaidgyroscope assemblies in approximat paral el sm, s m a si nal; pr du lngmeans :operatively connectedto said gyroscopeassemblies oneachmf said two. axes; of rotation of, each; yroscope assembly,

interconnecting means betwe n. the si ar. nal p oduc n two axes of "saidinstrument' otherandwith the; rotor windings of asecond.self-synchronous realternating 1 current.

relative to said two axes of.rota-; tion 2 oi} said gyroscope assemblies in accord-ancei2 8.. A. gyroscopic. device comprising, twosimilar independently mountedigyr'oscope assemblies including separate rotorsdriven in opposite1-direc=- tions of rotation on the respective spin axes theree' offand each gyroscopeassembly having means'i providing two' axes. of rotation with' correspond ing'axes of said gyroscope assemblies inapproxi mate parallelism, two self synchronous trans-+- mitters, means operatively connecting separate i. transmitters-to the respective" gyroscope asse1nlies on corresponding axes of rotation, a self-- synchronous receiver; statorwindings -of saiditwo transmitters being electrically connected in par= allel relation with eachotherand with the stator 1*" windings of saidself=synchronousreceiver; rotor windings in each" of said 1 transmitters for connection toan alternating current source, and means actuated by said self-synchronous receiver for establishing a datum relative to the corre.-

' sponding aXES'Of rotation of' said gyroscope as; semblies connected to said separate transmitters in'accordance with the average angular deviation of. the-two gyroscope assemblies about said cor* responding axes of rotation connected-to said transmitters;

9; A gyroscopic' device'comprising, two similar independently mounted gyroscope assemblies ine means'providing two axes" of rotation with cor-' responding axes of said gyroscope. assemblies" in" approximate parallelism, two signal "producin'g'de vices, means operatively connecting-separate signal producing devices. to therespective gyroscope assemblies on correspondingaxes-of rotation, in terconnecting means; between. said M two signal producing devices to provide a singl average sig nal output proportional to the average angular" displacement ofthe gyroscope assemblies about the corresponding axes of' rotation connected to' said signal producing devices, and means actuated by. said average signa'l'output for establishing a datum; relative to, the corresponding axes of rotation of said gyroscope assembliesconnected' to said two signal producing devices in accordance with the average angular deviation of the twogyroscope assemblies about said corresponding axes of rotation connected to said two; signal producing; devices.

HAROLD R; BEACOM.

REFERENCES. CITED The following references are of record in the: file of this patent:-

UNITED. STATES PATENTS France Feb. 18, 1925. 

